My 04 plate x-type has problems with the steering. it feels like the tyre presure is to low sometimes the other times it feels to much. the car wonders to either side when breaking. jaguar have suggested putting to new tyres on the car and then get the tracking sorted. ive been inderpendantly advised that replacing the perfectly good tyres want make any diffrence.

I would have an alignment donefirst and most reputable shops will perform a full check of your suspension to check for any damaged or excessively worn components and will advise you from there. If you have a complete matching set of tires and they are inflated properly to your vehicle specs and have been properly rotated every 10k miles then I believe you have a problem with your suspension. I would also check the condition of your brakes and another bit of info for you dependant of what tires you use some can have a very thin sidewall which can give you poor steering and handling around curves over 45mph you can check tire reviews online

Why dont you try putting the rear tires on the fronts? if the car pulls to one side that means one of the calipers is either binding or one caliper is not orking correctly